Transcript ppt - Max Planck Institut für Radioastronomie

ATLASGAL
APEX Telescope Large
Area Survey of
the Galaxy
F. Schuller, K. Menten, P. Schilke, et al.
Max Planck Institut für Radioastronomie
APEX Telescope Large Area
survey of the Galaxy
1. Survey definition
2. Instrumentation
3. Survey implementation
4. Perspectives
ATLASGAL : Survey definition
Aims:
• Unbiased survey of massive young stars + precursors for
massive protostars throughout the Galaxy
 provide a consistent database for follow-up
• Derive (proto-) IMF down to 0.1 Msol in a sample of nearby
regions
• Complementarity with Galactic surveys
wavelengths (MSX, GLIMPSE, Herschel…)
at
other
ATLASGAL : Survey definition
cf. IRAS :
massive star formation is mostly in | b | < 1°…
Black: all IRAS PSC
Blue: detected at 25
and 60 mm
Red: satisfy Wood &
Churchwell criteria
(compact HII regions)
ATLASGAL : Survey definition
cf. IRAS : massive star formation is mostly in |
< 1° but also some up to | b | = 2.5°
b|
IRAS
(IRIS)
25 mm
60 mm
100 mm
ATLASGAL : Survey definition
… and mostly in -80° < l < +90° :
IRAS in | b | < 1°
MSX in | b | < 0.5°: black=all
Blue = detected at 21mm
Red = with F21mm/F15mm > 2
ATLASGAL : Survey definition
Sensitivity: reach 1 Msol in nearby regions, and a few 10
Msol in Galactic Center
Gas mass in cores using Hildebrand (1983) and
standard physical parameters, b=2, Td=50 K:
Fn(870 mm)
d = 200 pc
d = 1 kpc
d = 3 kpc
d = 8 kpc
10 mJy
0.0033
0.083
0.75
5.3
30 mJy
0.010
0.25
2.25
16.0
50 mJy
0.017
0.42
3.75
26.5
100 mJy
0.033
0.83
7.5
53.3
ATLASGAL : Survey definition
Shallow survey
| l | < 80° ; | b | < 2.5° to one-s = 50 mJy
3-s detection of 0.3 Msol at 500 pc, 11 Msol at 3 kpc
Deep survey
| l | < 80° ; | b | < 1° to one-s = 10 mJy
3-s detection of 0.25 Msol at 1 kpc, 16 Msol in the GC
Deeper survey
below 0.1 Msol in limited parts of nearby regions
(e.g. s = 2 mJy in Rosette, 1.5 kpc)
Instrumentation : bolometer arrays
LABOCA Facility instrument:
• Large Bolometer Camera, 295 channels, 870 mm
APEX beam at 870 mm:
18’’= MSX pixels = Herschel at 250 mm
• field of view = 10’ x 10’
 large mapping speed
• pulse tube cooling down to 300 mK
• DC-coupled: total power signal, AC-biased
Instrumentation : bolometer arrays
LABOCA instrument: AC-biased => low 1/f noise
DC-biased (MAMBO)
AC-biased (SIMBA)
freq. (Hz)
freq. (Hz)
Instrumentation : bolometer arrays
Other arrays:
• APEX SZ (Berkeley ) Camera (talk by M. Pierre)
[ first light: Dec. 2005 ]
Instrumentation : bolometer arrays
APEX SZ Camera first light: 2005 Dec. 23
Instrumentation : bolometer arrays
Other arrays:
• APEX SZ (Berkeley ) Camera (talk by M. Pierre)
- 330 channels, 1.4 + 2 mm
- DC-coupled, pulse tube cooling
- Field of view = 0.4 x 0.4 deg2
=> mapping of large fractions of GP in short time
Galactic Plane = backup for average weather
870 mm + 1.4 mm + 2 mm => Tdust + spectral index
Instrumentation : bolometer arrays
APEX SZ Camera: noise spectrum
counts / sqrt(Hz)
raw data
correlated skynoise removed
Instrumentation : bolometer arrays
Other arrays:
- 37 element (MPIfR) at 350 mm
[ late 2006 ]
- currently being designed, will probably use same
technology as SIMBA :
cryostat, pairs of differentiated channels…
Small field of view => limited regions
ATLASGAL : implementation
First look survey
-Main goals:
• first global view in few months
• full census of most massive star forming sites,
also out the Galactic midplane, up to | b | = 2.5°
• demonstrate feasibility of the complete survey
- Area to observe:
• | l | < 80° ; | b | < 2.5° to one-s = 50 mJy
+ limited regions (10° long in | b | < 1°, Orion)
to s = 10 mJy
Total observing time: < 200 hours
ATLASGAL : implementation
Full survey
- Main goals:
• To have a complete census of high mass star
formation in the Galaxy
• To derive the protostellar IMF down to below 1 Msol
in a number of nearby regions
- Proposed area to observe at 870 mm:
-80° < l < +80° ; | b | < 1° to s = 10 mJy
+ nearby regions (e.g. Orion, Rosette, Chameleon,
Lupus, R CRa) even deeper
ATLASGAL : implementation
- Sensitivity: one-s = 10 mJy
• 0.4 Msol detected at 5-s at 1 kpc
• 30 Msol detected at 5-s in the Gal. Center
- Some limited areas in a few nearby massive star forming
regions down to 0.1 Msol
Total observing time: about 1000 hours
ATLASGAL : implementation
- Fast scanning speed:
e.g. 5’/s => 5 deg in 1 min., 5’ steps => 32 hours
to cover the area of the shallow survey
+ repeat with different angle = 64 hours
 Point source signature : 15 Hz
 also sensitive to extended emission
• Deep survey:
Repeat several coverages with high scanning speed to
reach required sensitivity
ATLASGAL : perspectives
- Follow up spectral line observations of (newly discovered)
cores, to derive kinetic distances, search for infall / outflows,
constrain temperatures, density structures, etc…
- extend to outer Galaxy
- combine with far-infrared (Herschel) and near-infrared
(GLIMPSE) surveys
ATLASGAL : conclusion
- This project is planned to be a long term project, to be
completed in the few first years of APEX scientific
operations
- This will make APEX a true Pathfinder for ALMA and
Herschel !
coordination: [email protected]